The method for automatic compensation and detection of earth faults in distribution network

The idea for a grounding neutral scheme for MV distribution networks is that when an instantaneous single-phase-to-earth fault occurs, the fault arc disappears automatically because of the rapid compensation of arc suppression coil current. The power supply is continuous. When a permanent single-phase-to-earth fault occurs it can detect and trip the faulty feeder in a short time. This scheme can be achieved by a TSC (thyristor switched capacitor) automatic tuning arc suppression coil with a parallel resistor. This paper presents the compensation principle of earth capacitance current and the detection methods of a faulty feeder. It also discusses the selection of the parallel resistor value. The simulation results based on EMTP-ATP show that this scheme is both correct and effective.